Aircraft engine attachment comprising at least one system for immobilizing a shear pin in translation comprising a stop plate, method for mounting said engine attachment and aircraft comprising said engine attachment

Abstract

An aircraft engine attachment connecting an attachment body and a primary structure of an aircraft pylon, the engine attachment comprising a shear pin immobilized in translation by a first immobilization system that comprises a shoulder and a removable stop that are integral with the primary structure, between which a flange of the shear pin is immobilized, and a second immobilization system that comprises a stop plate, connected by at least one removable link to the primary structure, which closes the first hole, at least in part.

The invention claimed is: 
     
       1. An aircraft engine attachment comprising:
 an attachment body connected to a primary structure of an aircraft pylon via an attachment body link comprising link elements and at least one shear pin that comprises a cylindrical body and a flange having a diameter greater than that of the cylindrical body,
 the attachment body link comprising, for each shear pin, a first hole in the primary structure and a second hole in the attachment body that are configured such as to accommodate the shear pin, the first hole comprising a shoulder against which the flange bears during operation in such a manner that the cylindrical body is positioned to straddle the first and second holes, 
 
 a first immobilization system that comprises, in addition to the shoulder, a removable stop, secured to the primary structure, configured such as to immobilize the flange between the shoulder and the removable stop, and 
 a second immobilization system that comprises a stop plate, connected by at least one removable link to the primary structure, which closes the first hole, at least in part, 
 wherein the attachment body link comprises at least one anti-rotation system for at least one of the link elements, each anti-rotation system comprising an anti-rotation plate that has a through-orifice with a section that complements a section of a head of the link element such that the stop plate and the head are immobilized in rotation relative to one another, and also a removable link for connecting said anti-rotation plate to the primary structure. 
 
     
     
       2. The aircraft engine attachment according to  claim 1 , wherein each anti-rotation plate is connected to the stop plate. 
     
     
       3. The aircraft engine attachment according to  claim 2 , wherein for each anti-rotation plate, the stop plate comprises an extension that has a passage orifice for a fixing element connecting the anti-rotation plate and the stop plate. 
     
     
       4. The aircraft engine attachment according to  claim 1 , wherein the stop plate comprises an orifice that has a diameter smaller than a diameter of the flange, positioned in line with the first hole when the stop plate is connected to the primary structure. 
     
     
       5. The aircraft engine attachment according to  claim 4 , wherein for each stop plate, the primary structure comprises an extension traversed by each removable link. 
     
     
       6. The aircraft engine attachment according to  claim 5 , wherein the removable link comprises two fixing elements, each being accommodated in passage holes of the stop plate and of the extension. 
     
     
       7. The aircraft engine attachment according to  claim 6 , wherein the stop plate comprises a recess in addition to the orifice. 
     
     
       8. An aircraft comprising an engine attachment according to  claim 1 . 
     
     
       9. A method for mounting an engine attachment comprising:
 an attachment body connected to a primary structure of an aircraft pylon via an attachment body link comprising link elements and at least one shear pin that comprises a cylindrical body and a flange having a diameter greater than that of the cylindrical body,
 the attachment body link comprising, for each shear pin, a first hole in the primary structure and a second hole in the attachment body that are configured such as to accommodate the shear pin, the first hole comprising a shoulder against which the flange bears during operation in such a manner that the cylindrical body is positioned to straddle the first and second holes, 
 
 a first immobilization system that comprises, in addition to the shoulder, a removable stop, secured to the primary structure, configured such as to immobilize the flange between the shoulder and the removable stop, and 
 a second immobilization system that comprises a stop plate, connected by at least one removable link to the primary structure, which closes the first hole, at least in part, 
 wherein the attachment body link comprises at least one anti-rotation system for at least one of the link elements, each anti-rotation system comprising an anti-rotation plate that has a through-orifice with a section that complements a section of a head of the link element such that the stop plate and the head are immobilized in rotation relative to one another, and also a removable link for connecting said anti-rotation plate to the primary structure, the method comprising the steps: 
 connecting the attachment body to an aircraft engine, 
 vertically moving the aircraft engine such as to position first and second contact faces of the primary structure of the aircraft pylon and of the attachment body opposite one another, 
 placing the link elements, 
 inserting each shear pin into the first and second holes until the flange is in contact with the shoulder, 
 placing the removable stop, and 
 positioning a stop plate and connecting the stop plate to the primary structure such as to close the first hole at least in part.